To use it, go to the Dialer's Dashboard and select the "INTERACTIONS" tab. Toggle the "tel:Links" option to on.
Sometimes (like the first time) Chrome will ask you to allow this action. Select "Allow".
Go to THIS TEST PAGE from any other browser that isn't Chrome. Find the example labeled "Already "tel:" Links" and click on the telephone number it's referencing. The Chrome browser will become active and pass the telephone number to the Dialer. Afterword the Dialer will make the call.
Some CRMs make it imposible to scrape numbers, so this feature is also functional within the Chrome browser itself.